Greg Stewart/SLAC National Accelerator Laboratory
Pulses of terahertz radiation shift neighboring atomic layers in the topological material tungsten ditelluride in opposite directions, distorting the material’s atomic structure. Following a pulse, the structure oscillates, with layers swinging back and forth around their original positions. Swinging in one direction, the material loses its topological properties. Swinging in the other direction, they become more stable. For clarity, motions have been exaggerated in this animation.